Blade-mounting



H. F. SCHMIDT.

BLADE MOUNTING.

APPLICATION FILED :umzzz. 191s.

Patented July WW.

A TTORNEYS.

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Herrera. sci-iivirnr, onierrrsnmaeir, rnnnsrnv'rinra, retreats reac es. a ori inal application: filed. March 31, 1917,

Tacit whom it may concern;

lle itkno'vvnthat I, l-lnnnr ll. Sci-inner,

a citizen oi? the United idtates, and a resident Of Pittsburgh, in the county of Allegheny and hitate-oi Pennsylvania, have made a new and 11863111.].111Vl3nl11011lIl Blade-Mounting, which is a division of an applicationfor patent, filed March 31, 1917, Serial No.

158,977, of which the following is a specification. f 1

This invention relates to blade mounting and particularly to that form of blade mounting used in fluid turbines and the like, and has for an object to produce a new and. improved blade mounting which is especially adapted to be employed in attaching blades to moving blade carrying elements.

it :hirther object is to. produce a riveted blade mounting in which means are pro vided to counteract eccentric loading of the parts forming the o1nt.

These and other ob ects are attained by means of the blade mounting described herein and illustrated in the accompanying drawing, where1n- @The figure is a diagrammatic sectional view of a blade mounting embodying the in volition. y

Turbine blades have frequently been mounted by inserting their shanks in a groove in the blade carrying element and by then securing each blade shank in place titi with one or more locking members such as rivets. The ordinary construction consists in a single groove in the blade carrying element and a single tongue on the blade'shank so that the rivets are in double shear. The

result would be the same it the blade shank straddled a single tongue on the blade carrying element. In either construction, the size of the rivet or rivets is limited by the pitch of the blades and. consequently by the amount of material which may be left in the shank. The number of rivets of a rea sonable size is limited for the same reason.

its the number and size oi? the rivets are limited, the strength and efficiency of the ioint are also limited in the single tongue and strengthoif the blade mounting by increasing the number oi. times some of the locking members or rivets are in shear. Although the number and slze oi: the memsipccification of Letters Patent.

Serial No. 158,977. 1918. Seria1 No. 241,433.

hivicled'aiulthis application filed June 2 2,

hers or rivets are limited as before, the

strength of the joint is greatly increased by *re wesrrnefi rousn Patented Pltnly 6, 1920s improvin'gthe efficiency of the joint. 111* throw all or a part of the locking members or rlvets in more than double shear and to 3 thereby increase the eilicienc'y and hence the strength oi? the joint. Obviously this may be done without increasing the weight of the oint, and at substantially the same cost as the cost of the old construction,"by increasing the number oi tongues inthe joint and by decreasing their thickness. It is evident that the e'lliciency of the joint is further increased by the greatly increased amount of surface, due to the multiple tongue construction, held in frictional engagement by the rivets.

In the figure T have illustrated a portion of a blade carrying element 5 and a portion of a blade 6, which is mounted on the blade carrying element 5. The shank of the blade 6 is shown as provided with three tongues 7, 8 and 9, which fit into grooves in the blade carrying element 5 and cooperate with two tongues 10 and 11, formed on the blade carrying element 5. The central tongue 8 of the blade shank is shown longer than the two side tongues 7 and 9, so that an inner locking member or rivet 12 passes through only the central tongue 8 and is therefore only in double shear. An outer locking member or rivet 13 passes through the tongues 'l', 10, 11. and 9 and is there fore in quadruple shear.

In order for the blade to tear away from the blade carrying element 5, it would be necessary for it to shear oil six rivet sections. lift the multiple tongue construction were not provided, the total number of rivet sections to be sheared oil would be only :iiour, consequently the strength of the joint has been increased by a shear area equal to twice the section of one of the rivets. This is accomplished without increasing the weight or cost of the joint, consequently the efi'iciency oi the oint is materially improved. This mounting is simple, compact, and makes possible a smooth continuous joint, due to the it 01 the tongues 7 and 9 against the blade carrying element 5 as shown.

tongues 7 and 9 constitutes the essential difference between the construction disclosed in the above mentioned application and the present construction. The outer flanges or tongues are reinforced against spreading Without the use of additional rivets and 0011- sequently the construction is simple and rigid. 7

While I have described and illustrated but .one embodiment of my invention, it will be apparent to those skilled in the art that various modifications, changes, additions and omissions may be made in the apparatus described and V illustrated without departing from the spirit and scope of the invention,

as set forth by the appended claims.

What I claim is:

1. A blade mounting comprising a blade shank provided with at least three tongues adapted to interleave with at least two tongues provided upon a blade carrying element, the free ends of the outer tongues having interlocking engagement with the adjacent portion of the inner tongues for preventing lateral displacement of the outer tongues, and means for preventim separation of the joint in a longitudinal direction.

2. A blade mounting comprising a shank element forming a multiple tongue groove joint with a blade carrying element, one of the said elements being provided with at least three tongues adapted to interleave with at least two tongues provided upon the other element, the free ends of the outer tongues having interlocking engagement with the adjacent portion of the inner tongues for preventing lateral displacement of the outer tongues, and means for preventing longitudinal separation of the 'oint.

In testimony whereof I have hereunto subscribed my name this 20th day of June,

HENRY F. SCHMIDT. Witness:

C. W. MCGHEE. 

